Code for the msqrt MathML tag

1999-11-17 01:40:04 +00:00 · 1999-11-17 01:40:04 +00:00 · 75448dae95
--- a/layout/mathml/base/src/nsMathMLmsqrtFrame.cpp
+++ b/layout/mathml/base/src/nsMathMLmsqrtFrame.cpp
@ -0,0 +1,258 @@
+/*
+ * The contents of this file are subject to the Mozilla Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/MPL/
+ * 
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ * 
+ * The Original Code is Mozilla MathML Project.
+ * 
+ * The Initial Developer of the Original Code is The University Of 
+ * Queensland.  Portions created by The University Of Queensland are
+ * Copyright (C) 1999 The University Of Queensland.  All Rights Reserved.
+ * 
+ * Contributor(s): 
+ *   Roger B. Sidje <rbs@maths.uq.edu.au>
+ *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
+ *   Vilya Harvey <vilya@nag.co.uk>
+ */
+
+
+#include "nsCOMPtr.h"
+#include "nsHTMLParts.h"
+#include "nsIHTMLContent.h"
+#include "nsFrame.h"
+#include "nsLineLayout.h"
+#include "nsHTMLIIDs.h"
+#include "nsIPresContext.h"
+#include "nsHTMLAtoms.h"
+#include "nsUnitConversion.h"
+#include "nsIStyleContext.h"
+#include "nsStyleConsts.h"
+#include "nsINameSpaceManager.h"
+#include "nsIRenderingContext.h"
+#include "nsIFontMetrics.h"
+#include "nsStyleUtil.h"
+
+#include "nsMathMLmsqrtFrame.h"
+
+//
+// <msqrt> and <mroot> -- form a radical - implementation
+//
+
+nsresult
+NS_NewMathMLmsqrtFrame(nsIFrame** aNewFrame)
+{
+  NS_PRECONDITION(aNewFrame, "null OUT ptr");
+  if (nsnull == aNewFrame) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  nsMathMLmsqrtFrame* it = new nsMathMLmsqrtFrame;
+  if (nsnull == it) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  *aNewFrame = it;
+  return NS_OK;
+}
+
+nsMathMLmsqrtFrame::nsMathMLmsqrtFrame() :
+  mSqrtChar(),
+  mSqrtBar()
+{
+   mSqrtChar.SetData(nsAutoString(PRUnichar(0x221A)));
+   mSqrtBar.SetData(nsAutoString(PRUnichar(0xF8E5)));
+}
+
+nsMathMLmsqrtFrame::~nsMathMLmsqrtFrame()
+{
+}
+
+NS_IMETHODIMP
+nsMathMLmsqrtFrame::Init(nsIPresContext&  aPresContext,
+                         nsIContent*      aContent,
+                         nsIFrame*        aParent,
+                         nsIStyleContext* aContext,
+                         nsIFrame*        aPrevInFlow)
+{
+  nsresult rv = NS_OK;
+  rv = nsMathMLContainerFrame::Init(aPresContext, aContent, aParent,
+                                    aContext, aPrevInFlow);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // TODO: other attributes...
+  return rv;
+}
+
+NS_IMETHODIMP
+nsMathMLmsqrtFrame::Paint(nsIPresContext&      aPresContext,
+                          nsIRenderingContext& aRenderingContext,
+                          const nsRect&        aDirtyRect,
+                          nsFramePaintLayer    aWhichLayer)
+{
+  nsresult rv = NS_OK;
+  
+  /////////////
+  // paint the content we are square-rooting
+  rv = nsMathMLContainerFrame::Paint(aPresContext, aRenderingContext, 
+                                     aDirtyRect, aWhichLayer);
+
+  if (NS_FRAME_PAINT_LAYER_FOREGROUND != aWhichLayer) {
+    return rv;
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    // paint the sqrt symbol
+    rv = mSqrtChar.Paint(aPresContext, aRenderingContext, mStyleContext);
+    // paint the overline bar
+    rv = mSqrtBar.Paint(aPresContext, aRenderingContext, mStyleContext);
+  }
+
+  return rv;
+}
+
+NS_IMETHODIMP
+nsMathMLmsqrtFrame::Reflow(nsIPresContext&          aPresContext,
+                           nsHTMLReflowMetrics&     aDesiredSize,
+                           const nsHTMLReflowState& aReflowState,
+                           nsReflowStatus&          aStatus)
+{
+  nsresult rv = NS_OK;
+  nsReflowStatus childStatus;
+  nsHTMLReflowMetrics childDesiredSize(aDesiredSize.maxElementSize);
+  nsSize availSize(aReflowState.mComputedWidth, aReflowState.mComputedHeight);
+
+  //////////////////
+  // Reflow Children
+
+  nsRect rect;
+  aDesiredSize.width = 0;
+  nsIFrame* childFrame = mFrames.FirstChild();
+  while (nsnull != childFrame) 
+  {
+    //////////////
+    // WHITESPACE: don't forget that whitespace doesn't count in MathML!
+    if (IsOnlyWhitespace(childFrame)) {
+      ReflowEmptyChild(aPresContext, childFrame);
+    }
+    else {
+      nsHTMLReflowState childReflowState(aPresContext, aReflowState,
+                                         childFrame, availSize);
+      rv = ReflowChild(childFrame, aPresContext,
+                       childDesiredSize, childReflowState, childStatus);
+      NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+
+      // At this stage, the origin points of the children have no use, so we
+      // will use the origins as placeholders to store the child's ascent and
+      // descent. Before return, we should set the origins so as to overwrite
+      // what we are storing there now.
+      childFrame->SetRect(&aPresContext,
+                          nsRect(childDesiredSize.descent, childDesiredSize.ascent,
+                                 childDesiredSize.width, childDesiredSize.height));
+
+      aDesiredSize.width += childDesiredSize.width;
+      if (aDesiredSize.ascent < childDesiredSize.ascent) {
+        aDesiredSize.ascent = childDesiredSize.ascent;
+      }
+      if (aDesiredSize.descent < childDesiredSize.descent) {
+        aDesiredSize.descent = childDesiredSize.descent;
+      }
+    }
+    rv = childFrame->GetNextSibling(&childFrame);
+    NS_ASSERTION(NS_SUCCEEDED(rv),"failed to get next child");
+  }
+  aDesiredSize.height = aDesiredSize.ascent + aDesiredSize.descent;
+
+  ////////////
+  // Prepare the radical symbol and the overline bar
+
+  nsIRenderingContext& renderingContext = *aReflowState.rendContext;
+  nsStyleFont font;
+  mStyleContext->GetStyle(eStyleStruct_Font, font);
+  renderingContext.SetFont(font.mFont);
+
+  // grab some metrics to help adjusting the placements
+  nsCOMPtr<nsIFontMetrics> fm;
+  nscoord ascent, descent; 
+  renderingContext.GetFontMetrics(*getter_AddRefs(fm));
+  fm->GetMaxAscent(ascent);
+  fm->GetMaxDescent(descent);
+
+  nsAutoString aData;
+  nsBoundingMetrics bm, bmdata[2];
+
+  // radical symbol  
+  mSqrtChar.GetData(aData);
+  renderingContext.GetBoundingMetrics(aData.GetUnicode(), PRUint32(1), bm);
+  bmdata[0] = bm;
+  nscoord charWidth = bm.width; // width of the radical symbol
+  nscoord charBearing = bm.rightBearing;
+
+  // overline bar
+  mSqrtBar.GetData(aData);
+  renderingContext.GetBoundingMetrics(aData.GetUnicode(), PRUint32(1), bm);
+  bmdata[1] = bm;
+  nscoord thickspace = bm.ascent - bm.descent; // height of the overline bar
+
+  // Stretch the sqrt symbol to the appropriate height if it is not big enough.
+  nsCharMetrics contSize(aDesiredSize);
+  nsCharMetrics desSize(descent, ascent, charWidth, ascent + descent);
+  mSqrtChar.Stretch(aPresContext, renderingContext, mStyleContext,
+                    NS_STRETCH_DIRECTION_VERTICAL, contSize, desSize);
+  charWidth = desSize.width;
+  if (aDesiredSize.ascent < desSize.ascent) {
+    aDesiredSize.ascent = desSize.ascent;
+  }
+  if (aDesiredSize.descent < desSize.descent) {
+    aDesiredSize.descent = desSize.descent;
+  }
+  aDesiredSize.height = aDesiredSize.ascent + aDesiredSize.descent;
+
+  mSqrtChar.SetRect(nsRect(0, thickspace, desSize.width, aDesiredSize.height));
+
+  // Stretch the overline bar to the appropriate width if it is not big enough.
+  contSize = nsCharMetrics(aDesiredSize);
+  desSize = nsCharMetrics(descent, ascent, bmdata[1].rightBearing-bmdata[1].leftBearing, ascent + descent);
+  mSqrtBar.Stretch(aPresContext, renderingContext, mStyleContext,
+                   NS_STRETCH_DIRECTION_HORIZONTAL, contSize, desSize);
+  nscoord dy = bmdata[1].ascent - ascent;
+  mSqrtBar.SetRect(nsRect(charBearing, dy, desSize.width, thickspace));
+
+  // Update the size of the container
+  aDesiredSize.width += charWidth;
+  aDesiredSize.ascent += thickspace;
+  aDesiredSize.height = aDesiredSize.ascent + aDesiredSize.descent;
+
+  //////////////////
+  // Place Children now by setting the origin of each child.
+  nscoord chX = charWidth;
+  nscoord chY; // = thickspace;
+  childFrame = mFrames.FirstChild();
+  while (nsnull != childFrame) {
+    if (!IsOnlyWhitespace(childFrame)) {
+      childFrame->GetRect(rect);
+      // rect.y was storing the child's ascent, from earlier.
+      chY = aDesiredSize.ascent - rect.y;
+      childFrame->MoveTo(&aPresContext, chX, chY);
+      chX += rect.width;
+    }
+    rv = childFrame->GetNextSibling(&childFrame);
+    NS_ASSERTION(NS_SUCCEEDED(rv),"failed to get next child");
+  }
+
+  if (nsnull != aDesiredSize.maxElementSize) {
+    aDesiredSize.maxElementSize->width = aDesiredSize.width;
+    aDesiredSize.maxElementSize->height = aDesiredSize.height;
+  }
+  aStatus = NS_FRAME_COMPLETE;
+  return NS_OK;
+}
+
--- a/layout/mathml/base/src/nsMathMLmsqrtFrame.h
+++ b/layout/mathml/base/src/nsMathMLmsqrtFrame.h
@ -0,0 +1,90 @@
+/*
+ * The contents of this file are subject to the Mozilla Public
+ * License Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.mozilla.org/MPL/
+ * 
+ * Software distributed under the License is distributed on an "AS
+ * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ * 
+ * The Original Code is Mozilla MathML Project.
+ * 
+ * The Initial Developer of the Original Code is The University Of 
+ * Queensland.  Portions created by The University Of Queensland are
+ * Copyright (C) 1999 The University Of Queensland.  All Rights Reserved.
+ * 
+ * Contributor(s): 
+ *   Roger B. Sidje <rbs@maths.uq.edu.au>
+ *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
+ *   Vilya Harvey <vilya@nag.co.uk>
+ */
+
+#ifndef nsMathMLmsqrtFrame_h___
+#define nsMathMLmsqrtFrame_h___
+
+#include "nsCOMPtr.h"
+#include "nsMathMLContainerFrame.h"
+
+//
+// <msqrt> -- form a fraction from two subexpressions 
+//
+
+/*
+The MathML REC describes:
+
+The <msqrt> element is used to display square roots.
+The syntax for <msqrt> is:
+  <msqrt> base </msqrt>
+
+Attributes of <msqrt> and <mroot>:
+
+None (except the attributes allowed for all MathML elements, listed in Section
+2.3.4). 
+
+The <mroot> element increments scriptlevel by 2, and sets displaystyle to
+"false", within index, but leaves both attributes unchanged within base. The
+<msqrt> element leaves both attributes unchanged within all its arguments.
+These attributes are inherited by every element from its rendering environment,
+but can be set explicitly only on <mstyle>. (See Section 3.3.4.) 
+*/
+
+/*
+TODO:
+*/
+
+class nsMathMLmsqrtFrame : public nsMathMLContainerFrame {
+public:
+  friend nsresult NS_NewMathMLmsqrtFrame(nsIFrame** aNewFrame);
+
+  NS_IMETHOD
+  Init(nsIPresContext&  aPresContext,
+       nsIContent*      aContent,
+       nsIFrame*        aParent,
+       nsIStyleContext* aContext,
+       nsIFrame*        aPrevInFlow);
+
+  NS_IMETHOD
+  Reflow(nsIPresContext&          aPresContext,
+         nsHTMLReflowMetrics&     aDesiredSize,
+         const nsHTMLReflowState& aReflowState,
+         nsReflowStatus&          aStatus);
+
+  NS_IMETHOD 
+  Paint(nsIPresContext&      aPresContext,
+        nsIRenderingContext& aRenderingContext,
+        const nsRect&        aDirtyRect,
+        nsFramePaintLayer    aWhichLayer);
+
+protected:
+  nsMathMLmsqrtFrame();
+  virtual ~nsMathMLmsqrtFrame();
+  
+  virtual PRIntn GetSkipSides() const { return 0; }
+
+  nsMathMLChar mSqrtChar, mSqrtBar;
+};
+
+#endif /* nsMathMLmsqrtFrame_h___ */
+